Amtrak, the nation’s federally supported passenger rail service, has long been a whipping boy on Capitol Hill — often accused of being a “bloated bureaucracy” with little ridership, poor service and wasteful spending.

Although American passenger rail still faces political and financial challenges, it is “on the track to success,” said a study released this month by the Washington-based Brookings Institution.

The Brookings report, “A New Alignment: Strengthening America’s Commitment to Passenger Rail,” said overall Amtrak ridership was up 55 percent last year over 1997. North Carolina’s figures reflect that as well. The Carolinian, which runs a 704-mile route from Charlotte to New York, reports a 32-percent increase in riders from 1997 to 2012. More eye-opening is the massive growth in shorter in-state trips. The Piedmont, which travels from Charlotte to Raleigh, ticketed 47,000 passengers in 1997 and a whopping 162,857 in 2012. That’s a 278-percent increase.

Of course, that amounted to a small fraction of the 31 million total annual Amtrak riders, which is an all-time high and growing.

Most of the growth has been on short-distance corridors like the rapidly growing Piedmont — routes shorter than 400 miles. There seems little doubt that many people in the Piedmont are traveling by rail to do business in Raleigh or Charlotte these days. With no end to higher gas prices in sight, that’s not likely to change.

Brookings attributed Amtrak’s improved performance, in part, to its partnership with 15 states that have paid at least a portion of the operating expenses for 21 routes. North Carolina is one of them. In fact, North Carolina is among Amtrak’s partnership success stories, according to Brookings.

At the moment, North Carolina is the only state contributor to the Carolinian’s Charlotte to New York route. And the Piedmont, which began in 1995, is unique to other routes because the N.C. Department of Transportation designed and owns the cars and operates the tracks under the auspices of the state-owned North Carolina Railroad Co., which also leases the tracks to Norfolk Southern Railroad for freight services. North Carolina has been able to meet higher demand for service on the Piedmont because it is responsible for its own tracks and improvements via a public-private partnership.

Lines like the Piedmont are valuable for operators and customers. According to the Brookings report, 83 percent of passengers nationally travel less than 400 miles combined, Amtrak’s short-distance corridors made money in 2011, while the longer routes lost money.

Among other recommendations, the Brookings study suggested better collaboration on long-distance routes; a dedicated federal funding source for passenger rail, coupled with more flexibility for states; and improved state-private partnerships that could add privately financed routes beyond Amtrak. We like the last two suggestions.

Lawmakers as well as stakeholders must weigh what continues to make sense. The growth of short lines like the Piedmont is a clear indication that it is a significant transportation option. And it could be a key engine toward our economic potential.